Methods for Plasma Treatment on a Can Component, Feedstock &amp; Tooling

ABSTRACT

Methods are disclosed for applying a protective layer to a can component and for modifying surface properties of a can component, feedstock or tooling. An example method involves: (a) directing a precursor plasma plume at a surface of a can component via at least one precursor plasma gun, where the precursor plasma plume includes an ionized gas and an ionized precursor and (b) treating at least a portion of the surface of the can component with the precursor plasma plume and thereby forming a first layer on the portion of the surface of the can component treated with the precursor plasma plume.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

Many beverages contain diary which require pasteurization to slowspoilage caused by microbial growth. Milk or milk based products may bepackaged, pasteurized and distributed in cans. For example, afterfilling cans with milk, the milk may be pasteurized at about 260° F. forabout 30 minutes. As such, if the can is not coated prior to beingfilled with milk, pasteurization may cause the bottom of the can todarken. To avoid this discoloration, a retort process may be used tocoat the can bottoms. During a rinse stage of the retort process, thecans may be rinsed in washer water that includes zirconium phosphate.However, using too much zirconium phosphate may result in peeling of thelithography and using too little zirconium phosphate may result in thecan bottoms turning brown. In addition, the washer fluids have to bedrained on the back end after the rinse process completes, which may belabor and time intensive. On the front end, the zirconium phosphatesolution has to be heated to a certain temperature for the coatingprocess to be effective, which may cause delays in the coating process.Still further, the zirconium phosphate coating should not be applied tothe neck area to avoid the lithography flaking in the neck area and thismay be difficult to achieve during the rinse process.

SUMMARY

Example embodiments beneficially provide methods for applying aprotective layer to a can component and/or for modifying surfaceproperties of a can component. More specifically, example embodimentsmay generally relate to a precursor plasma plume that includes anionized gas and an ionized precursor that may treat a beverage cancomponent and form a layer on the surface of the can component. Thislayer may advantageously protect the can component from variousenvironmental effects, for example, browning during the retort processor moisture and salty air encountered during transport that could causecorrosion, among other possibilities. In a further embodiment, thislayer may have the benefit of being energy-adjusting in nature.

In addition, the can making process has been improved so that all cancomponents may be made efficiently and at relatively low cost. Much ofthis efficiency may be attributed to the ability to cut, draw, iron,form, and trim at exceptionally high speed with minimal variation.However, in order to increase speed, friction forces should be minimizedto limit heat, wear, and variation, for example, within the fabricationprocess. Thus, the ability to add a tightly bound, anti-friction layersignificantly reduces heat and part wear within many locations in thecan and end manufacturing process.

Other example embodiments, may generally relate to a precursor-freeplasma plume that includes an ionized gas that may treat a beverage cancomponent and change the surface properties thereof. Altering thesurface properties of the beverage can component may advantageouslyinclude, for example, (i) adjusting the surface energy to promote evenwetting or dewetting of ink, lube, water or other secondary materials,(ii) adding functional groups to the surface to promote laydown of inkthrough improved wetting, (iii) aid in removing contaminants from thesurface by improved lubricant wetting of a metal surface, and/oradjusting can component surface energies that may aid in directing ordistributing secondary materials to targeted zones on the surface of thebeverage can component, (iv) dewetting to create specialized textures ofink and/or varnish, (v) dewetting to promote sheeting of washing orrinsing to prevent residual contaminants during drying, among otherpossibilities.

Other example embodiments, may generally relate to a precursor plasmaplume or a precursor-free plasma plume that may treat a beverage cancomponent and alter the surface properties of the beverage cancomponent. This may have one or more beneficial effects, including (i)aiding in preferential bonding of applied materials, (ii) addingfunctional groups to the surface to improve bonding to ink, for example,(iii) adding a precursor coating to aid in adhesion of liners, such ascompound sealant in a seam, for example, or adding a function coating toaid in adhesion of a liner of can component such as CapCan cap, amongother possibilities.

In addition, the precursor plasma plume and the precursor-free plasmaplume may beneficially be applied via one or more plasma guns that mayhave a controllable footprint to aid in precise treatment applications.For example, the plasma plumes may be directed at a can component suchthat the plasma treatment and any resulting protective layer or alteredsurface properties remain on the targeted surface of the can. Inaddition, a plasma gun may be beneficially used to administer plasma toa specific feature of a can component, such as a score of a can end, bytracing the score with the plasma plume of the plasma gun. In addition,the precursor layer may be created to protect exposed areas of a cancomponent that has been created by other mechanical or high energy meanssuch as stamping or laser etching of features. Plasma also has the addedbenefit of remaining close to room temperature and therefore may notheat up the can components, permitting easier handling of the cancomponents during the manufacturing process. Plasma coatings may also besubjected to high temperatures from ovens without compromising theintegrity of the coating. Lastly, plasma treatment may permit the use ofan alkaline washer and eliminate the need for hydrofluoric acid washesused with the zirconium phosphate retort treatment that may pose ahealth hazard.

Thus, in one aspect, a method for applying a protective layer to a cancomponent is provided including the features of (a) directing aprecursor plasma plume at a surface of a can component via at least oneprecursor plasma gun, where the precursor plasma plume includes anionized gas and an ionized precursor and (b) treating at least a portionof the surface of the can component with the precursor plasma plume andthereby forming a first layer on the portion of the surface of the cancomponent treated with the precursor plasma plume.

In a second aspect, a method for modifying surface properties of a cancomponent is provided including the steps of (a) directing aprecursor-free plasma plume at a surface of a can component via at leastone precursor-free plasma gun, where the precursor-free plasma plumecomprises an ionized gas, wherein the surface of the can component iscontoured or has a score and (b) treating at least a portion of thesurface of the can component with the precursor-free plasma plume.

In a third aspect, a method is provided including the steps of (a)directing a precursor plasma plume at a surface of at least one of a cancomponent, feedstock and tooling via at least one precursor plasma gun,where the precursor plasma plume comprises an ionized gas and an ionizedprecursor and (b) treating at least a portion of the surface of the atleast one of the can component, the feedstock and the tooling with theprecursor plasma plume and thereby forming a first layer on the portionof the surface of the at least one of the can component, the feedstockand the tooling treated with the precursor plasma plume.

In a fourth aspect, a method is provided including the steps of (a)directing a precursor-free plasma plume at a surface of at least one ofa can component, feedstock and tooling via at least one precursor-freeplasma gun, wherein the precursor-free plasma plume comprises an ionizedgas, wherein the surface of at least one of the can component, thefeedstock and the tooling is contoured or has a score and (b) treatingat least a portion of the surface of the can component, the feedstockand the tooling with the precursor-free plasma plume.

These as well as other aspects, advantages, and alternatives, willbecome apparent to those of ordinary skill in the art by reading thefollowing detailed description, with reference where appropriate to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is side view of a can body, according to one example embodiment.

FIG. 2 is a top view of can end, according to one example embodiment.

FIG. 3 is a cross-sectional view of a plasma gun known in the art,according to one example embodiment, that is configured to emit a plasmaplume.

FIG. 4 is a flow chart of a method according to one example embodimentfor forming a layer on a can component.

FIG. 5 is a flow chart of a method according to one example embodimentfor changing surface properties on a can component.

DETAILED DESCRIPTION

Example methods for applying a protective layer to a can componentand/or for modifying surface properties of a can component are describedherein. Any example embodiment or feature described herein is notnecessarily to be construed as preferred or advantageous over otherembodiments or features. The example embodiments described herein arenot meant to be limiting. It will be readily understood that certainaspects of the disclosed apparatus and methods can be arranged andcombined in a wide variety of different configurations, all of which arecontemplated herein.

Furthermore, the particular arrangements shown in the Figures should notbe viewed as limiting. It should be understood that other embodimentsmay include more or less of each element shown in a given Figure.Further, some of the illustrated elements may be combined or omitted.Yet further, an example embodiment may include elements that are notillustrated in the Figures.

As used herein, “plasma” refers to a gas, which may include a precursorin some embodiments, that has been ionized and excited to a higherenergy state using high frequency, high voltage radio frequency or othermethod capable of producing plasma, for example, such that the plasmamay contain atoms, molecules, positive ions and electrons and negativeions together with un-ionized material. Ionization of the gas and/orprecursor may be induced via application of heat, an electric field oran electromagnetic field.

As used herein, an “ionized gas” may include, but are not limited to,argon, oxygen, nitrogen, dry air, nitrous oxide, trifluoroethane,tetrafluoromethane, or mixtures thereof. These gases may or may notremain ionized throughout before reacting with an identical or differentmolecule or with the surface of a beverage can component.

As used herein, a “precursor” is a molecule of low molecular weightcapable of being ionized and reacting with identical or differentmolecules of low molecular weight to form a layer on a surface. Exampleprecursors may include, but are not limited to, monomers (includingsiloxane-based monomers, such as hexamethyldisiloxane (“HDMSO”) orhexamethyldisilazane (“HMDSN”)), tetraethyl orthosilicate (“TEOS”),substituted organic siloxanes, acrylates, fluorinated acrylates,trifluoroethylene, trifluoroethane, epoxies, ethylene oxides, ethyleneglycols, carbonates, methanol, ethylene diamine, styrene, solubilizedmetals, fluorinated oligomers, saturated oligomers, or mixtures thereof.These precursors may take the form of a gas or an aerosolized liquid orsolution.

As used herein, “about” means +/−5%.

As used herein, a “can component” refers to a can body that hassidewalls and a bottom, a metal can bottle, a can end, a dome that maybe seamed to a can body, a cap that may be attached to a dome, or othermetal container component. The can bodies may be subjected to a seriesof processing operations including one or more of a blank and draw intoa shallow cup, a redraw and iron to lengthen the sidewalls, a trim ofthe open end of the cup, a wash and dry, an outside coat, an oven-heateddry of the outside coat, a printing operation on the outside coat, a rimcoat of the bottom of the can, an oven-heated dry of any printing ink,an application of a protective spray on the inside of the can body, anoven cure of the protective spray, fluting of the sidewalls of the canbody, forming of a neck and flange at the open end of the cup body or alonger neck and bottle finish, and/or reforming of the bottom surfaceinto a dome, among other possibilities. The term “can body” may refer tothe various forms of the cup during any one of the various processingoperations. An example can body 100 that has been processed through theforegoing manufacturing steps is shown in FIG. 1. The can body 100 mayhave a neck 105 and a flange 110, as well as a sidewall 115. As usedherein, if the can body 100 is at an advanced processing stage, a“sidewall” 115 may include the flange 110 and neck 105 components. Inother embodiments, earlier in the can processing stage, the sidewall 115may be short resulting in a shallow cup or the sidewall may be drawn andironed without a neck 105 or flange 110. The can body 100 may alsoinclude a bottom 120 having a dome 125 and a rim 130, if the can body isin an advanced stage of processing. In other embodiments, earlier in thecan processing stage, the can bottom 120 may be substantially flat. Eachof the foregoing features of the can body may or may not be present forthe plasma treatment depending on the stage of processing.

The can ends may also go through a series of processing operationsincluding one or more of a press to form can end blanks, a curl of thecan ends' edge, application of a compound sealant in the curl of the canends, scoring of the can ends, and application of tabs to the can ends,among other possibilities. The term “can end” may refer to the variousforms of the can end during any of the various processing operations. Anexample can end 200 that has been through the foregoing manufacturingprocesses is shown in FIG. 2. The can end 200 may have a tab 205 coupledto a main panel 210 via a rivet 215, for example. The tab 205 may definea tab tongue 206 and a horseshoe lance 207. The main panel 210 maydefine an outer downward facing curl 211. A main score 220 may beprovided on the surface of the main panel 210 and define a deboss panel225. An anti-fracture score 230 and a D-bead 235 may each be defined onthe deboss panel 225. A vent coin 240 may be provided along theanti-fracture score 230. A nose coin 245 may also be provided on themain panel 210. Each of the foregoing features of the can end may or maynot be present for the plasma treatment depending on the stage ofprocessing.

Each of the features of the can body and the can end may be selectivelytreated with plasma to create different surface properties or coatings.Alternatively, the various features of the can body or can end may becollectively treated with plasma at the same time to achieve the samecoating or surface properties. The methods disclosed herein may involvea precursor plasma plume or a precursor-free plasma plume directed at asurface of the can body or can end during or in between any of theforegoing operations to form a can body or a can end or other cancomponent during or after operations to couple the can end to the canbody. In addition, the surface of the can component in the path of theplasma plume may be an inner surface or an outer surface of the cancomponent. In addition, the precursor plasma plume and theprecursor-free plasma plume may be applied to the can component inseries. The precursor plasma plume may be applied before or after theprecursor-free plasma plume depending on the desired effect on the cancomponent.

Alternatively the can body may have a longer neck and a bottle finish,such as ROPP threads or an end adapted to receive a Maxi P closure or acrown. The ROPP, Maxi P or crown closures are also contemplated underthe definition of a can component.

Another alternative is that the can body may be seamed to a metal domethat may have a twist on/off cap. The metal dome may be made via a blankand draw and subjected to a series of processing operations, includingforming the shape and rolling the edge. The cap may have a liner made ofa flexible film or may be a formed with a liner that adheres to the cap.For example, in operation, a preformed cap may enter into a linermachine, the cap may be preheated, a dollop of preformed liner materialmay be added to the cap, then a forming tool compresses the dollop toshape the liner into the desired geometry necessary to effectively sealthe can dome.

In some embodiments, the methods described herein may be used to treataluminum sheet feedstock instead of a can component described above. Thefeedstock may be cut and formed into a cup to form the start of a canbody.

The can component manufacturing process is unique due to high speed(creating up to 2000 to 3000 can components per minute or more), lowtolerances, exacting manufacturing processes, and food safetyrequirements. The higher speeds and the extreme processing conditionsseen downstream may require adaptions to introduce plasma treatment intothe processing methods. Plasma treatment may be beneficially introducedduring known bottlenecks or slower processing segments, among otherpossibilities.

Manufacturing of can components may be done using contact tooling thatmay have excessive wear due to a manufacturing process runs nearlycontinuously at a high rate of components per minute. In someembodiments, the methods described herein may be used to treat contacttooling. This may lower the coefficient of friction thereby decreasingwear of this expensive and specialized tooling. This contact tooling maybe used to manufacture the can components discussed above.

The present embodiments advantageously provide methods for applying aprotective layer to a can component and/or for modifying surfaceproperties of a can component. Referring now to FIG. 3, one embodimentof a precursor plasma gun 300 is shown defining a housing 305 that hasan insulator 306. An electrode 310 may be centrally disposed in thehousing 305 between a metering plate 315 and a nozzle head 320. Theelectrode 310 may be coupled to power supply 325. In one embodiment, theelectrode may energize the plasma gun with an electric potential of atleast about 5,000 volts. A gas chamber 330 may be defined by the housing305 between the metering plate 315 and the back end 335 of the plasmagun 300 located opposite to the nozzle head 320. A gas inlet 340 maydefined in housing 305 in the area defining the gas chamber 330. Inoperation, a gas may advance through a supply line to the gas inlet 340and into the gas chamber 330 and then pass through a plurality of holes316 defined in the metering plate 315 and to the electrode 310. Anelectric potential from the electrode 310 may then transition the gasinto plasma 345 in a discharge zone 311 of the housing 305, the plasma345 may exit the plasma gun 300 as a plasma plume 346 via the nozzlehead 320 and be directed at a surface of a can component 350. In thisembodiment, a precursor inlet 355 is defined in the nozzle head 320 nearthe end of the electrode 310. In operation, a supply line 356 feeds aprecursor gas or precursor aerosolized solution through the precursorinlet 355 into the flowing plasma 345 in the nozzle head 320 and theprecursor exits the nozzle head as part of the plasma plume 346. In oneembodiment, the precursor inlet may not be present or the precursorsupply may not be flowing such that this is a precursor-free plasma gun.If the precursor supply is flowing, then this is a precursor plasma gun.The precursor-free and precursor plasma guns are discussed with respectto the methods 400 and 500 below.

FIG. 4 is a flow chart of a method 400 that includes, at block 405,directing a precursor plasma plume at a surface of a can component viaat least one precursor plasma gun. In this embodiment, the precursorplasma plume comprises an ionized gas and an ionized precursor. Then, atblock 410, the precursor plasma plume treats at least a portion of thesurface of the can component thereby forming a first layer on theportion of the surface of the can component treated with the precursorplasma plume. In operation, the components of the plasma stream may bondand polymerize, for example, forming a first layer on the surface of thecan component. In various embodiments, the first layer may include asiloxane network, such as glass, a small molecule or metal layer, orpolymer network. In one embodiment, the first layer may be at least oneatom thick and may range up to about 1000 nm.

In one embodiment, the can component may include aluminum or steel,among other possibilities. In an alternative embodiment, in whichcontact tooling is the target of the plasma treatment, tooling mayinclude carbon nitride, tungsten carbide or other hardened materials.The foregoing materials may have the benefit of being generallynon-reactive.

In a further embodiment, methods 400 may beneficially reduce VOCemissions and be carried out under atmospheric pressure. Alternatively,methods 400 and 500 may be carried out under vented conditions or undervacuum.

In an additional embodiment, treating at least the portion of thesurface of the can component with the precursor plasma plume may includeflowing a precursor plasma from the precursor plasma plume along acontour of the surface of the can component. For example, in a furtherembodiment, the can component may include a sidewall coupled to a bottomsurface that defines a dome and a rim. In this embodiment, the precursorplasma plume may be directed at the dome and the precursor plasma mayflow from the precursor plasma plume along the dome and treat the domesuch that the first layer is formed on the dome. The plasma treatment inthis embodiment may be applied by a single precursor plasma gun directedat the center of the dome or by a plurality of precursor plasma gunsdirected at evenly spaced targets about the dome. In a furtherembodiment, the single precursor plasma gun may be used to treat a cancomponent for about 25 to about 1000 milliseconds, and in a furtherpreferred embodiment the can component may be treated with plasma forabout 400 milliseconds. For larger can components such as aluminum sheeton coils, the treatment would be continuous and the component movedrelative to the plasma gun. The treatment times noted herein may beadjusted based upon a variety of factors, such as the flow rate of thegas, the number of plasma guns, and/or the size or configuration of thedesired treatment area. For example, in one embodiment, treatment of asheet of aluminum feedstock with plasma may be continuous as the sheetmoves relative to the plasma plume.

In an alternative embodiment, the precursor plasma plume may instead bedirected at the rim, and the precursor plasma may flow from theprecursor plasma plume along the rim, the dome and a portion of thesidewall and treat these features such that the first layer is formed onthe rim, the dome and the portion of the sidewall. In this embodiment, aplurality of precursor plasma guns may be utilized and be evenly spacedabout the rim. In a further embodiment, four precursor plasma guns maybe used. In a still further embodiment, each can component may betreated with plasma by the four precursor plasma guns for about 10milliseconds to about 4000 milliseconds. For example, advancing 300 cancomponents per minute, may permit each to be treated for 200milliseconds. In an additional embodiment, a single precursor plasma gunmay be utilized and directed at the rim. In this embodiment, each canbottom may be treated with plasma for about 500 milliseconds to about1000 milliseconds, or more preferably about 750 milliseconds, which mayallow about 80 cans per minute to be processed. In further embodiments,a plurality of plasma guns may be arranged in series and the cancomponent may be advanced past each of the plasma plumes. In embodimentsin which a precursor-free plasma plume is used instead, the plasma mayflow and treat in a similar manner but instead of forming a protectivelayer, the surface properties of the can component may be changedinstead, as discussed in more detail below with respect to method 500.

In another embodiment, at least the portion of the surface of the atleast one of the can component, the feedstock and the tooling may betreated with the precursor plasma plume. For example, at least a portionof the surface of the tooling may be treated, and a precursor plasma mayflow from the precursor plasma plume along at least one of a contour, acrevice, a score, a joint and an indentation of the surface of thetooling. In a further embodiment, one or more of a contour, a crevice, ascore, a joint and an indentation on the surface of the tooling may betraced with the precursor plasma plume or with the precursor-free plasmaplume.

In still another embodiment, a plurality of precursor plasma plumes maybe directed at the feedstock. The plurality of precursor plasma plumesmay be arranged adjacently or with overlapping footprints. At least theportion of the surface of the feedstock may be treated with theplurality of precursor plasma plumes and precursor plasma may flow fromthe plurality of precursor plasma plumes along the surface of thefeedstock such that the first layer is formed on the feedstock.

In addition to forming a first layer on the portion of the surface ofthe can component treated with the precursor plasma plume, the precursorplasma plume may also beneficially alter the surface properties of thecan component. For example, in one embodiment, a contaminant orsecondary material present on the portion of the surface of the cancomponent treated with the precursor-free plasma plume may be removed.In another embodiment, the surface energy of the portion of the surfaceof the can component treated with the precursor plasma plume may beraised or lowered. In a still further embodiment, functional groups maybe added to the portion of the surface of the can component treated withthe precursor plasma plume. The benefits and effects of changing thesurface energy or surface properties of the can component are discussedin more detail with respect to method 500.

In another embodiment, at least one precursor plasma gun may have anozzle outlet and the nozzle outlet may be arranged at least about 0.1mm to about 1 cm, and preferably about 1 mm to about 5 mm, away from thesurface of the can component during coating. In another embodiment, thenozzle of each of the plasma guns may be angled from about 0 to about 90degrees, preferably about 35 degrees to about 90 degrees relative to thetarget surface of the can component.

In a further embodiment, the precursor plasma and precursor-free plasmamay preferably flow at about 20 psi to about 100 psi, or more preferablyat about 40 psi.

In one embodiment, the at least one precursor plasma plume may be asingle precursor plasma plume that has a footprint sized to match afootprint of the can component. The size of the footprint of the plasmaplume may be controlled by altering the distance of the plasma gunnozzle from the surface of the can component. For example, the footprintof the plasma plume may increase as the distance of the plasma plumefrom the target surface of the can component increases. Increasing thedistance of the plasma plume from the target surface of the cancomponent may also result in a plasma plume with a lower energy density.In another embodiment, method 400 may include rotating the can component360 degrees in a path of a single precursor plasma plume. In thisembodiment, the plasma plume may be arranged closer to the surface ofthe can component to maintain a higher energy density plasma plume. Thisembodiment may be useful in applying a plasma treatment to the rim ofthe can bottom or in applying a plasma treatment to the neck and/orflange of the sidewall, for example. This embodiment may also be usefulwith a precursor-free plasma plume applied to the inner surface of thecurl of a can end, for example, to facilitate the bond between thesurface of the can curl and a sealing compound. In an alternativeembodiment, the plasma plume may also be applied to a continuous roll ofsheet aluminum, to coat or clean the feedstock as it entersmanufacturing.

In various embodiments, the precursor plasma plume and/or theprecursor-free plasma plume may be used to trace (i) exposed aluminum ona can component, such as a score, (ii) a can component feature withweakened coating, such as mechanical or laser marking, or (iii) otherhighly-worked can component features such as threading or rivets on thesurface of a can component. In operation, the plasma gun may bephysically moved to trace the targeted can component. Alternatively, asupport holding the can component may move the can component in the pathof the plasma plume to trace the score, for example. In one embodiment,the precursor-free plasma may be used to clean the score and then theprecursor plasma plume may be used to apply a protective sealing layerto the score.

In another embodiment, the at least one precursor plasma plume mayinclude four precursor plasma plumes, including a central precursorplasma plume and three peripheral precursor plasma plumes. The centralprecursor plasma plume may be aligned with a central axis of the canbottom and the three peripheral precursor plasma plumes may be alignedwith the rim of the can bottom and may be spaced equidistantly apartfrom each other. The same arrangement of plasma plumes may be utilizedfor a precursor-free plasma plume.

Each of the foregoing arrangements and embodiments may be utilized withrespect to a precursor-free plasma plume unless the context dictatesotherwise.

FIG. 5 is a flow chart of a method 500 that is provided that includesthe step 305 of directing a precursor-free plasma plume at a surface ofa can component via at least one precursor-free plasma gun. In thisembodiment, the precursor-free plasma plume comprises an ionized gas.This embodiment also provides that the surface of the can component iscontoured or has a score. Then at step 510, method 500 includes treatingat least a portion of the surface of the can component with theprecursor-free plasma plume.

In one embodiment, method 500 may be implemented in series with method400 either before or after method 400 has been used to treat the surfaceof a can component. In this embodiment, method 500 and the variousembodiments that follow may be used to treat any surface of the cancomponent and are not limited to a surface of the can component that iscontoured or has a score.

In one embodiment, method 500 may also include the step of removing atleast one contaminant, oxide layer, previously applied coating or othersecondary material present on the portion of the surface of the cancomponent treated with the precursor-free plasma plume. In operation,the precursor-free plasma plume may remove contaminants by breakingapart organic bonds and/or reacting with contaminants resulting invapors or gases that leave the surface of the can component.Alternatively, the force of the plasma flow against the surface of thecan component may evacuate contaminants from the target surface such asdust or weakly held molecules.

In another embodiment, method 500 may include raising the surface energyof a portion of the surface of the can component coated with theprecursor-free plasma plume. Changing the surface energy of the cancomponents to be higher energy than that of a pre-existing coating ortreatment and may improve the can component's ability to be wet. Forexample, if ink is desired on a surface, increasing the surface energywould increase the wetability of the ink to the can component surface.If an even coat of polymer is desired, then increasing the surfaceenergy above that of the target polymer may help the polymer laydown inthe desired area of the can component. In another example, a subsequentchemical treatment may more evenly cover the surface of a highlyenergized surface.

In another embodiment, method 500 may include lowering the surfaceenergy of a portion of the surface of the can component. Lowering thesurface energy of the can component to a point lower than that of apre-existing coating, treatment, or lubricant on the surface of the cancomponent will improve the can component's ability to dewet or aid insheeting of a coating, treatment, or lubricant. For example, rinsingstages of the can manufacturing process often contain contaminants thatmay concentrate through drying and create potential defects. Improveddewetting may beneficially allow sheeting of rinse stages to prevent anyliquid from remaining on the surface of the can component and may lowerdrying time and energy required. In another example, dewetting maycreate desired features by causing preferential thinning of inks andvarnishes in treated areas, so that the ink or varnish may have atextured feel on the can component.

In another embodiment, method 500 may include adding functional groupsto the surface of a portion of a can component. Adding these functionalgroups may allow for a strong, covalent bond between the can componentand another material or other can component. In a further embodiment,the functional group may remain active, as a free radical, and mayinitiate a reaction with a precursor, coating, or other can component,for example, bonding a liner to a cap.

The above detailed description describes various features and functionsof the disclosed apparatus and methods with reference to theaccompanying figures. While various aspects and embodiments have beendisclosed herein, other aspects and embodiments will be apparent tothose skilled in the art. The various aspects and embodiments disclosedherein are for purposes of illustration and are not intended to belimiting, with the true scope and spirit being indicated by thefollowing claims. The various aspects of the methods and the variousembodiments may be combined unless context dictates otherwise.

1. A method, comprising: directing a precursor plasma plume at a surfaceof a can component via at least one precursor plasma gun, wherein theprecursor plasma plume comprises an ionized gas and an ionizedprecursor; and treating at least a portion of the surface of the cancomponent with the precursor plasma plume and thereby forming a firstlayer on the portion of the surface of the can component treated withthe precursor plasma plume.
 2. The method of claim 1, furthercomprising: directing a precursor-free plasma plume at the surface ofthe can component via at least one precursor-free plasma gun, whereinthe precursor-free plasma plume comprises an ionized gas; and treatingat least a portion of the surface of the can component with theprecursor-free plasma plume.
 3. The method of claim 2, furthercomprising: removing at least one contaminant or secondary materialpresent on the portion of the surface of the can component treated withthe precursor-free plasma plume.
 4. The method of claim 2, furthercomprising: raising or lowering the surface energy of the portion of thesurface of the can component treated with either the precursor-freeplasma plume or the precursor plasma plume.
 5. The method of claim 2,further comprising: adding functional groups to the portion of thesurface of the can component treated with either the precursor-freeplasma plume or the precursor plasma plume.
 6. The method of claim 1,wherein the first layer is at least one atom thick.
 7. The method ofclaim 1, further comprising: energizing the at least one precursorplasma gun with an electric potential of at least about 5,000 volts. 8.The method of claim 1, wherein at least one precursor plasma gun has anozzle outlet and the nozzle outlet is arranged at least about 0.1 mm toabout 1 cm away from the surface of the can component during treatment.9. The method of claim 1, wherein treating at least the portion of thesurface of the can component with the precursor plasma plume comprisesflowing a precursor plasma from the precursor plasma plume along acontour of the surface of the can component.
 10. The method of claim 1,wherein the can component is a sidewall coupled to a bottom surface thatdefines a dome and a rim, wherein directing the precursor plasma plumeat the surface of the can component via the at least one precursorplasma gun comprises directing the precursor plasma plume at the dome,and wherein treating at least the portion of the surface of the cancomponent with the precursor plasma plume comprises flowing a precursorplasma from the precursor plasma plume along the dome such that thefirst layer is formed on the dome.
 11. The method of claim 1, whereinthe can component is a sidewall coupled to a bottom surface that definesa dome and a rim, wherein directing the precursor plasma plume at thesurface of the can component via the at least one precursor plasma guncomprises directing the precursor plasma plume at the rim, and whereintreating at least the portion of the surface of the can component withthe precursor plasma plume comprises flowing a precursor plasma from theprecursor plasma plume along the rim, the dome and a portion of thesidewall such that the first layer is formed on the rim, the dome andthe portion of the sidewall.
 12. The method of claim 1, wherein the atleast one precursor plasma plume is a single precursor plasma plume,wherein a footprint of the single precursor plasma plume is sized tomatch a footprint of the can component.
 13. The method of claim 1,further comprising: rotating the can component 360 degrees in a path ofa single precursor plasma plume.
 14. The method of claim 1, furthercomprising: tracing a score on the surface of a can component with theprecursor plasma plume.
 15. The method of claim 2, further comprising:tracing a score on the surface of a can component with theprecursor-free plasma plume.
 16. The method of claim 1, wherein the atleast one precursor plasma plume comprises a plurality of precursorplasma plumes spaced apart from each other and each directed at a targetportion of the surface of the can component.
 17. The method of claim 1,wherein the can component comprises aluminum.
 18. A can componenttreated according to the method of claim
 1. 19. A method, comprising:directing a precursor-free plasma plume at a surface of a can componentvia at least one precursor-free plasma gun, wherein the precursor-freeplasma plume comprises an ionized gas, wherein the surface of the cancomponent is contoured or has a score; and treating at least a portionof the surface of the can component with the precursor-free plasmaplume.
 20. The method of claim 19, further comprising: after treatingthe portion of the surface of the can component with the precursor-freeplasma plume, directing a precursor plasma plume at the surface of thecan component via at least one precursor plasma gun, wherein theprecursor plasma plume comprises an ionized gas and an ionizedprecursor; and treating the portion of the surface of the can componentwith the precursor plasma plume and thereby forming a first layer on theportion of the surface of the can component treated with the precursorplasma plume.
 21. The method of claim 19, further comprising: removingat least one contaminant or secondary material present on the portion ofthe surface of the can component treated with the precursor-free plasmaplume.
 22. The method of claim 19, further comprising: raising orlowering the surface energy of the portion of the surface of the cancomponent treated with the precursor-free plasma plume.
 23. The methodof claim 19, further comprising: adding functional groups to the portionof the surface of the can component treated with the precursor-freeplasma plume.
 24. A can component treated according to the method ofclaim
 19. 25.-45. (canceled)